Antiurolithiatic Activity of the Leaf Extracts of Maerua Angolensis

A wide range of medicinal plants have been used conservatively for urolithiaisis due to their fewer side effects and because they contain copious phytochemicals that show advantageous effects in urolithiasis. Maerua angolensisis traditionally used in the treatment of urolithiasis in Eritrea. It is a small African tree growing west to Senegal, in Somalia, Ethiopia, and south to Natal. Maerua angolensis (keremo) was selected as there are no scientific reports available on the plant for anti-urolithiatic activity. In vitro anti-urolithiatic activity of the plant extracts was tested in terms of inhibition of calcium oxalate nucleation, aggregation and growth assays in the presence as well as absence of inhibitors. Three different concentrations (10mg/ml, 20mg/ml, and 30mg/ml) of the plant extracts were tested in each assay. Phytochemical screening revealed the presence of alkaloids, flavonoids, amino acids, tannins, phenols, saponins, resins, carbohydrates and proteins. Among all the extracts of M. angolensis, the highest percentage nucleation inhibition was obtained from water extract at a concentration of 30 mg/ml (95.5%). The aqueous, chloroform and ethanol extracts (10 and 30 mg/ml) were found to possess significant anti-urolithiatic activity when compared to standard Cystone (10 and 30 mg/ ml). In the aggregation assay, the highest percentage aggregation inhibition was obtained from chloroform extract at a concentration of 30mg/ml (196.25%). The chloroform extracts (10, 20, 30 mg/ml) was found to have anti-urolithiatic activity with significant difference when compared with cystone (standard drug). As revealed in the comparison of the percentage growth inhibition by the three extracts of M. angolensis, the chloroform extract at the concentration of 30 mg/ml was found to be the most effective. The highest percentage dissolution of calcium oxalate of Maerua angolensis was found from ethanol extract at the concentration of 30mg/ml (55.73%). The aqueous extract (10 and 20 mg/ml) was statistically different when compared to Cystone standard (10 and 20 mg/ml). The study concludes that the leaf extracts of Maerua anglensis have inhibitory effect on calcium oxalate for crystal nucleation, aggregation and crystal growth. It also showed great efficacy in the dissolution of calcium oxalate crystals. Thus these extracts may be valuable resources for treatment of urolithiasis.

Keywords: Urolithiasis; Maerua angolensis; Nucleation assay; Aggregation assay; Growth assay

Abbreviations: UV: Ultraviolet; MAA: Maerua Angolensis Aqueous; MAE: Maerua Aangolensis Ethanol; MAC: Maerua Angolensis Chloroform